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Hi All just finished my Alternative BCM fixing, i know you can buy other units but i thought i would try and help out especially now money is getting tight,
Firstly replaced the Convenience battery, then fitted a Victron energy Cyrix-ct intelligent battery combiner 12/24v-230 amp,
Secondly fitted a CAN BUS Emulator (for the dreaded Battery light on the dash)
Thirdly fitted a remote intelligent Battery disconnector 200amp continuous 800amp instantaneous,
now everything is working as it should for around £200,
pictures attached, before some of you guy's say this is wrong, its working and keeping the cars on the road for people to enjoy as some of these replacement BCM's are quite expensive,
It doesn't look the best but it all fits nicely behind the panels with no modifications,
I Hope this help's
Hi There Kustom1911
The CAN Bus Emulator i brought from EBAY ( its posted from America)
look up Mercedes R230 battery light Emulator on ebay and it should come up, as for the wiring diagram all you have is a little black box with a pair of canbus cables going on to the can bus rail which is bottom left hand of the SAM behind the rear seat uk driver side, its a bit fiddly and the you just have a positive wire connection and a negative wire connection that is it, the diagram how to fit comes with the unit about £140 delivered, and ive tried everything on my car to make sure all things work ie roof
windows work as they should and charging at 14.32volts so happy days at the moment and also no risk of the unit catching fire, if you need anymore info please don't hesitate to contact me, good luck.
Ciao Kustom1911
L'emulatore CAN Bus l'ho comprato da EBAY (è stato spedito dall'America).
Cerca su eBay l'emulatore della spia della batteria Mercedes R230 e dovrebbe apparire. Per quanto riguarda lo schema elettrico, tutto quello che hai è una piccola scatola nera con una coppia di cavi CAN Bus che vanno alla guida CAN Bus che si trova in basso a sinistra del SAM dietro il sedile posteriore lato conducente nel Regno Unito. È un po' complicato e hai solo un collegamento del filo positivo e un collegamento del filo negativo, tutto qui. Lo schema di come montarlo è incluso nell'unità, costa circa 140 £ e ho provato tutto sulla mia auto per assicurarmi che tutte le funzioni, ad esempio
i finestrini del tetto funzionano come dovrebbero e si caricano a 14,32 volt, quindi per il momento sono felice e non c'è rischio che l'unità prenda fuoco. Se hai bisogno di altre informazioni non esitare a contattarmi, buona fortuna.
Hi, nice work, could you give me the link to the emulator? I can't find it on eBay, thanks
Last edited by antonioreal88; Jul 2, 2025 at 01:26 AM.
Thanks for posting your solution. Frankly I like it better than replacing the BCM with an aftermarket DC-to-DC converter. Just running the two batteries in parallel with some isolation makes sense.
Its that or simply eliminating the front battery.
Hi There Kustom1911
The CAN Bus Emulator i brought from EBAY ( its posted from America)
look up Mercedes R230 battery light Emulator on ebay and it should come up, as for the wiring diagram all you have is a little black box with a pair of canbus cables going on to the can bus rail which is bottom left hand of the SAM behind the rear seat uk driver side, its a bit fiddly and the you just have a positive wire connection and a negative wire connection that is it, the diagram how to fit comes with the unit about £140 delivered, and ive tried everything on my car to make sure all things work ie roof
windows work as they should and charging at 14.32volts so happy days at the moment and also no risk of the unit catching fire, if you need anymore info please don't hesitate to contact me, good luck.
Could you please provide the name of the eBay seller for the emulator? Thanks!
Amazing if your name is "Doc" Brown but I wouldn't touch it personally.
I'd rather sell the Mercedes to be honest. Once the BCM is failing there will be other issues most likely so if you are tight on money this is a very difficult vehicle to own.
If it all can be done for around $250 USD then it is a good solution for a guy whose battery control module needs to be replaced for whatever reason. The OP says all is fine afterwards and everything is working as it should..
